Cystatin C In Peripheral Blood Can Detect The Damage Of Renal Function Earlier

Objectives1:To study the significance of Cystatin C (Cys C) in early detection of the graft function after renal transplantation.2:This index was used in detecting the graft function. Meanwhile we rearch the relationship between Cystatin C and GFR (glomerular filtration rate). Through compared with Scr, to show the vulue of Cystatin C as an index in detecting the graft function after renal transplantation. And the value of cystatin C (Cys C) in the early detection of the graft function damagement after renal transplantation and providing evidence for the further diagnosis and treatment in Urology.MaterialThe concentrations of Cys C, Blood urea nitrogen (BUN), Serum creatinine (SCr), and glomerular filtration rate (GFR) were measured. According to the results of the post-transplantation GFR; Seventy renal post-transplanted patients were assigned into 3 groups:group A (31 cases with the normal range of the renal function, GFR≥90 ml/min/1.73 m2), group B (27 cases with Scr≤133μmol/L and 60<GFR<90 ml/min/1.73 m2), and group C (12 cases with Scr>133μmol/L and 60<Ccr<90 ml/min/1.73 m2). Meanwhile,60 cases with normal renal function were applied as control group.Results1:Cys C concentration in normal control group was 0.72±0.13 mg/L. Scr concentration was 50.48±15.20μmol/L.2:The Cys C concentration in group B (1.37±0.14) was significantly higher than it in group A (0.96±0.10) (P=0.0000<0.01).3:Scr concentration in group B (27 cases) were (105.26±13.76)μmol/L, the difference has no statistically significance (P>0.05), compared with that of group A (90.51±9.86)μmol/L.4:The SCr and the Cys C demonstrated linear correlations with the GFR in all groups of A, B and C. The correlation coefficients (r) in each group were -0.7272 and-0.7439,-0.7072 and -0.7543,-0.7430 and -0.7669; respectively.5:The Cys C concentration in group A (0.96±0.10)mg/L was significantly higher than it in group normal (0.96±0.10) mg/L (P=0.0000<0.01).6:The concentration of Scr, Cystatin C and BUN had no conspicuous statistically significance (P>0.05), compared with the normal control pre-transplantati on.Conclusions:Serum creatinine (Scr) level is commonly used to estimate renal function, however, Scr is affected by not only its renal excretion, but also its production mainly from muscular tissue. Scr is also highly dependent on age, weight, and gender. It leads to adjust the Scr value by these factors for estimating renal function, especially in renal transplant recipients. Rapid and accurate evaluation of renal function from glomerular filtration rate (GFR) is important in follow-up of renal transplant patients for detecting rejection and adapting drug dosage.Cystatin C (Cys C), a cationic basic protein, is a cysteine proteinase inhibitor and involves in intracellular protein catabolism. It has a constant producing rate by all nucleated cells before being freely filtered at the glomeruli. Then Cys C is almost completely reabsorbed and catabolized in the proximal tubular cells. Cys C has therefore been evaluated as an endogenous marker for GFR in patients with various renal diseases and the different stages of renal failure.In this study, we tested if the Cys C is correlated with the GFR. The Modification of Diet in Renal Disease (MDRD) equation calculating the value of the GFR. The MDRD equation for classification of chronic kidney disease was supposed as an excellent marker for GFR. We found that:Compared with the Scr, Cys C has a better correlation with Ccr when graft function was normal or renal function was slightly impaired. Post- transplantation, when grafts function was damaged slightly, the Cys C had a more sensitive changement, espiacially when the Scr concentration had not changed.Cys C concentration was not influenced by diet、infection et. Cys C, as a more rapid, sensitive index, could be used in the early detection of renal function impairment after transplantation,even can be used in Urology.